Fluid-based switches, such as liquid metal micro switches (LIMMS) have been made that use a liquid metal, such as mercury, as the switching element. The liquid metal may make and break electrical contacts. Alternately, a LIMMS may use an opaque liquid to open or block light paths. To change the state of the switch, a force is applied to the switching fluid, which causes it to change form and move.
Substrates used to manufacture the LIMMS may be held together with adhesives, such as polymers. The adhesives used may not withstand some assembly conditions (e.g., soldering temperatures). Additionally, polymers may absorb gases and/or moisture and may outgas during use, which may cause chemical contamination of the interiors of the package. Polymers also do not seal hermetically, so additional sealing is required to create a hermetic switch.
In one embodiment, a method for producing a switch is disclosed. The method comprises depositing a first alignment pad on a first substrate. A second alignment pad is deposited on a second substrate. Solder is then deposited on at least one of the alignment pads. A switching fluid is also deposited on the first substrate. The substrates are mated together by aligning the alignment pads and heating the solder. A cavity holding the switching fluid is defined between the two substrates, the cavity sized to allow movement of the switching fluid between first and second states.